Apparatus for burning pulverized fuel.



Patented m. 29, 190i.

G. S. EMERICK. APPARATUS FOB BURNING PULVERIZED FUEL.

(Application filed July 24, 1900.)

2 Sheets-Sheet l.

(No Model.)

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No. 666,862'. 9 Patented Jan. 29, MIL

G. S. EMERICK.

APPARATUS FOR BUBNING'PULVEBIZED FUEL.

- (Application filed July 24, 1900.)

(No Model.) 2 Sheets-Shoat 2.

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GEORGE S. EMERICK, OF PHILADELPHIA, PENNSYLVANIA.

APPARATUS FOR BURN ING PULVERIZED FUEL.

SPECIFICATION forming part of Letters Patent No. 666,862, dated January 29, 1901. Application filed July 24, 1900. Serial No. 24,669. (No model.)

To aZZ whom it may concern: 4

Be it known that I, GEORGE S. EMERICK, a citizen of the United States, residing at No. 703 Lippincott Building, in the city and county of Philadelphia and State of Pennsylvania, have invented new and useful Improvements in Apparatus for Burning Pulverized or Finely-Divided Coal or other Similar Fuel, of which the following is a specificatwo.

My invention relates to that class of apparatus wherein the fuel preliminarily reduced to a finely-divided state is injected into the furnace under air or steam pressure; and one object is to provide a means whereby to secure in the use of such fuels a more complete combustion and consequent utilization of heat energy than is attainable through existing devices.

A further object of my. invention is to provide an efficient means for automatically controlling the feed of such pulverized fuel into the furnace.

Iattain these objects by the mechanism illustrated in the accompanying drawings, in which Figure 1 is a general view, in side elevation, of the entire apparatus. Fig. 2 is a View in plan of the means whereby the rate of feed of the fuel is controlled; and Fig. 3 is a sectional view, on a larger scale, of a portion of the feed-controlling means shown in Fig. 2, showing a controlling device forming a feature of the invention.

In Fig. 1, 1 is a crushing, grinding, or pulverizing mill of any suitable description wherein coal or similar fuel may be reduced to a relatively fine or granulated state. The mill is actuated by the pulleys 3, belting 4,

and shafting 5, and the stationary engine 6,,

of any suitable description, the ungronnd fuel being fed into the mill through the chute or hopper 2.

At 7 I have indicated a separator of the class wherein particles of a predetermined grade of fineness are separated from the residue of the material by the action of air-currents of regulated intensity. I designate, preferably, for this purpose the air-separator for which Letters Patent of the United States have been granted me, No. 609,537, dated August 23, 1898. The separator 7 is actuated by the pulleys 8, belting 9, shafting 5, and stationary engine 6 and communicates through the outlet 48 with the couveyer 11 and through the outlet 47 with the storage-cham ber 13. The mill 1 communicates with the separator 7 by means of the chute 10. The conveyer 11 is of any suitable description. One end communicates with the separator through the pipe 48 and the other with the chute or hopper 2. The worm 12 is actuated by the gears 14. One end of the inclosing casing of said worm communicates with the storage-chamber 13 and the other end through the opening 49 with the discharge-pipe 16. The fan or blower 15, of any suitable description, is actuated by the stationary engine 6, and supplies an air-blast through the discharge-pipe 16, which passes through the opening in the front 18 of the furnace 50.

At 17 I designate the mechanism (shown in detail in Figs. 2 and 3) wherebythe rate of rotation of the worm 12 is automatically controlled in the manner hereinafter described. I designate, preferably, for this purpose the Reeves speed-changing mechanism for which Letters Patent No. 584,402 were granted June 15, 1897. This mechanism is actuated by the stationary engine 6.

In Fig. 2, 21 is a supporting-frame carrying the shafts 22, 23, 24, and 25. The shaft 22 is rotated by the pulley 26 and carries the pulley 27, formed in separate halves adapted to be withdrawn from or moved toward each other in the manner hereinafter described. The shaft 24 carries a similar pulley 28, connected with the pulley 27 by the belt 29. The rotation of the shaft 24 is communicated by the pulley 30 to the gears 14, as shown in Fig. l. The shafts 23 and 25 are provided with right-hand screw-threads for about one half their length and with left-hand threads for the remaining half and carry the screwthreaded collars 33 and 32. The pulleys 27 and 28 are keyed upon the shafts 22 and 24, rotating therewith,while freely slidable thereon. The hubs 34 and 35 of said pulleys are provided with the collars 36 and 37, controlling said hubs. Levers 31 engage the collars 36, 37, and 32 by teats or projections thereon, as shown in Fig. 2, and said levers are fulcrumed upon the collars 33, which constitute nuts upon the threaded shaft 23. The doublewith the boiler 19, Fig. '1, by the pipes 53 and i 41 and is provided with the piston-head 42,

piston-rod 43, and the spring 44, coiled between the piston-head and the end of the steam-cylinder. The piston-rod 43 controls the double-headed pawl 38 by means of the short connecting-strap 54.

In Fig. 3, 45 is a screw-threaded gland passing through the end of the steam-cylinder 40 and carrying the diaphragm 46, which operates to compress the spring 44 in the manner hereinafter described.

The operation of my invention is as follows: Coal or any other suitable fuel is fed into the hopper 2, Fig. 1, and crushed to a relatively fine state in the mill 1. Thence the crushed product passes by the chute 10 to the separator 7, where particles of a predetermined grade of fineness are separated from the residue by the sifting or weighing action of air-currents of regulated intensity, as is in my said Letters Patent therefor more particularly set forth and described. The product. thus obtained for consumption as fuel should be of about one-hundred-aud-fifty-mesh fineness or of about the fineness of lampblack.

The separated product passes through the outlet 47 into the storage-chamber 13. The residue passes through the outlet 48 into the conveyor 11, by which it is carried up to the hopper 2 and again passed through the mill 1. The crushed fuel is thus made to pass successively and repeatedly through the mill 1 and separator 7, only that portion which is of the required grade of fineness being extracted by the separator '7 and allowed to pass by the outlet 47 into the storage-chamber 13. From the storage-chamber 13 the pulverized fuel passes by gravity into the rotating worm 12, by which it is fed at a uniform rate into the discharge-pipe 16 through the com municating passage 49. As fast as the fuel is fed into the discharge-pipe it is injected or blown into the furnace 50 by the air-blast generated by the fan 15, which communicates with said discharge-pipe.

In existing apparatus for the utilization of granulated fuel the preliminary com minution of the fuel is not carried to a sufficiently high point, and this comparative coarseness of the particles injected into the furnace carries with it certain defects.

It is undesirable to introduce air into the furnace in quantity greater than that which is requisite to effect a complete combustion of the fuel, as any excess over this quantity not only does not aid combustion, but. in fact retards it, operating to lower the temperature of the furnace and to carry ofif heat which might otherwise be utilized to assist combustion. Itis obvious that all the superfluous air present passes off with the chimney temperature, causing a loss of heat measured by the weight of such air, its specific heat, and a number of degrees through which its temperatu re is raised.

In the employmentof ground fuel it is requisite that it be maintained in suspension while combustion is in progress, and in existing apparatus this is accomplished by blow ing the fuel into the furnace mixed with air at high pressure. Now the high air-pressure requisite to drive the fuel through the burner or discharge-pipe and maintain it in suspension in the furnace inevitably carries with it the defect above referred tonamely, an excess of air beyond that required for the purposes of combustion, with the attendant consequences of a lowered furnace temperature and waste of heat. Even with. such high pressure a considerable portion of the fuel falls to the bed of the furnace, where a layer of live coal has to be kept up to consume it. Furthermore, the fuel passes through the greater part of the furnace before combustion takes place, if atall. In myimproved apparatus the fineness of the fuel product obtained is is such that the high air-pressures ordinarily required to maintain ground fuel in suspension in the furnace are not only unnecessary, but undesirable. A comparatively low pressure can be employed, with the result that the fuel is not driven throughout the length of the furnace before combustion takes place. On the contrary, an instantaneous conversion is effected into a gaseous form and a practically complete combustion takes place within a short distance from the orifice of the discharge-pipe 16. The. low air-pressure has this further advantage that no excess of air is thereby introduced beyond the quantity requisite to effect complete combustion. No bed of live coal either for purposes of ignition or to consume such portion of the fuel as is not burned in suspension is required in my improved apparatus. The injected fuel is entirely consumed while in suspension and ignites upon the application of flame after the manner of gas.

It being desirable that a uniform steampressure should be maintained in the boiler 19, I have provided a means whereby the rate of discharge of the pulverized fuel with the furnace 50 is automatically controlled by said steam-pressure, increasing when the pressure diminishes and decreasing when the pressure increases beyond the predetermined maximum. The operation of the means whereby this is accomplished is as follows: The rate of rotation of the worm 12 is controlled by the speed-changingmechanism, (indicated at 17 in Fig. 1 and shown in detail in Figs. 2 and 3.) The operation of this device is as follows: The pulley 26, actuated by the stationary engine 6, Fig. 1, rotates the shaft 22 and the pulley 27, formed in truncated coneshaped halves, mounted thereon. The pulley 27 actuates the similar pulley 2S, shaft 24, and pulley 30 by means of the belt 29. The pulley 30 is belted to the gears 14, which in turn actuate the worm 12, as shown in Fig. 1. The gear relation between the pulleys 27 and 28 varies as the distance from the centers of the shafts 22 and 24 to the belt 29. In the position of the pulleys 27 and 28 shown in Fig. 2 it is obvious that the pulley 28 is being rotated at a higher rate of speed than the pulley 27 and the fuel is being fed into the discharge-pipe 16, Fig. 1, at a correspondingly high rate. To reduce the rate of feed, the shaft 25, Fig. 2, is so rotated as to draw the collars 32 toward the middle of the shaft, and with them the ends of the levers 31 connected therewith. The levers 31 being pivoted upon the collars 33 on the shaft 23, the approximation of the ends of said levers on the shaft 25 simultaneously draws together the halves of the pulley 28 and draws apart the halves of the pulley 27. This alters proportionally the gear relation between the pulleys 27 and 28 and lowers the rate of rotation of pulley 28, thus producing a lower rate of rotation in the worm 12, and a consequent reduction in the rate of fuel feed into the furnace.

Hitherto in the use of the above-described speed-changing mechanism the change in speed has been effected by giving the shaft 25 the requisite number of turns by some means, such as the application of a wrench to the squared end of said shaft. By the mechanism shown in Figs. 2 and 3 I am enabled to automatically control the rate of rotation of the speed-changer, making it directly dependent upon the steam-pressure in the boiler 19.

The shaft 22, Fig. 2, imparts a slight reciprocal motion to the double-headed pawl 38. The heads 51 and 52 of said pawl are adapted to en gage the teeth on either side of the ratchet 39. The pawl is pivoted at 55 and is connected with the piston-rod 43 by the strap 54 in the manner shown, whereby the piston-rod controls the lateral position of the pawl without interfering with the reciprocal movement of the latter. The spring 44 in the steam-cylinder 40 is of such tension that while a predetermined steam-pressure is maintained in the boiler, Fig. 1, and through the steam-pipe 41 against the piston-head 42 the latter is in equilibrium and neither head of the pawl 38 engages the ratchet 39. If the furnace temperature rises too high, and thus increases the steam pressure beyond the predetermined amount, the piston-head 42 is pushed slightly down, and the descending piston 43 brings the head 51 of the reciprocating pawl 38 into contact with the ratchet 39, which is thereby rotated, rotating the shaft 25 and drawing together the collars 32 and the ends of the levers 31 mounted thereon, whereby the halves of the pulley 27 are drawn apart and those of the pulley 28 are drawn together. This decreases proportionately the speed of the pulley 28, and consequently decreases the rate of feed. When the decreased feed has lowered the furnace temperature and steam-pressure, the spring 44 restores the piston-head 42 to its original position, thus disengaging the pawl-head 51 and ratchet 39. If for any reason the furnace temperature and steampressure become unduly lowered, the pistonhead 42 will rise, pushed by the expansion of the spring 44, and the head 52 of the pawl will rotate the ratchet, so as to reverse the movements of parts above described and increase the rate of fuel feed.

The spring 44 may be adapted to maintain a fixed steam-pressure, as shown in Fig. 2, or by the addition of the means shown in Fig. 3 the spring tension and steam-pressure may be altered or readjusted at will. The screwthreaded gland 45 passes through the end of the steam-cylinder 40 and carries the diaphragm 46, between which and the pistonhead 42 the spring 44 is compressed. By screwing or unscrewing the gland 45 the compression of the spring 44 can be increased or diminished, correspondingly increasing or diminishing the steam-pressure at which the piston-head 42 will act.

What I claim as my invention, and desire to secure by Letters Patent, is

1. The combination in apparatus for the pulverization and utilization of fuel, of a mill for the reduction of said fuel, a separator, a worm, a speed-changing mechanism adapted to control said worm, a discharge-pipe, means such as the fan 15 for ejecting said fuel from said discharge-pipe and means such as the ratchet 39, pawl 38, steam-cylinder 40, communicating with a steam-generator, pistonhead 42, piston 43 and spring 44 for automatically controlling said speed-changing mechanism, substantially as described.

2. In combination in an apparatus for the reduction and combustion of fuel, a reducingmill, a separator receiving the reduced product therefrom and separating the finer portion thereof from the residue, a discharge-pipe, a fan supplying an air-blast to said dischargepipe, a worm regulating the feed of said fuel into said discharge-pipe, a speed-changing mechanism actuating said worm and means such as the reciprocating pawl 38, ratchet 39, cylinder 40, communicating with a steam-generator, piston-head 42,piston-rod 43 and spring 44 for automatically controlling said speedchanging mechanism, substantially as described.

3. In combination in an apparatus for the reduction and combustion of fuel, a mill wherein said fuel is reduced, a separator wherein the finest portion of the reduced fuel is separated from the residue, a conveyer, a storage-chamber, a discharge-pipe, a fan generating an air-blast in said discharge-pipe, a worm intermediate between said storagechamber and said discharge-pipe, a speedchanging mechanism actuating and regulating the rate of rotation of said worm and means such as the ratchet 39, reciprocating pawl 38, steam -cylinder 40, communicating with a steam-generator, piston-head 42, pie-- ton-rod 43 and spring 44 for automatically controlling said speed-changing mechanism, substantially as described.

4. The combination in apparatus for the combustion of pulverized fuel, of a grindingmill for reducing the fuel to powdered form, an aspirating centrifugal separator for separating the finer from the coarser particles of the powdered mass, a discharge-pipe for delivering said lighter separated particles into the furnace, and means for generating an airblast in said pipe, the aspirating centrifugal separator being located above the said discharge-pipe, whereby there is but a slight lift of the fine particles necessary to effect their separation, said particles then passing by gravity to the discharge-pipe, substantially as specified.

5. The combination in apparatus for the combustion of pulverized fuel, of a grindingmill for reducing the fuel to powdered form, an aspiratiug centrifugal separator for separating the finer from the coarser particles of the powdered mass, a discharge-pipe for delivering said lighter separated particles into the furnace, a feed-regulator disposed between the separator and the discharge-pipe, and means for generating an air-blastin said discharge -pipe, the aspirating centrifugal separator being located above the feed-regulator, whereby there is but a slight lift of the fine particles necessary to effect their separation, said particles then passing by gravity to the feed-regulator and thence to the discharge-pipe, substantially as specified.

6. The combination in apparatus for the combustion of pulverized fuel, of a reservoir for said fuel, a blast apparatus for projecting the fuel into the furnace, a feeding device for conveying the powdered fuel from the reservoir to said blast apparatus, and speed-changing mechanism for said feeder, comprising a ratchet-wheel having teeth on both faces, the teeth of one face being right-handed and those of the other left-handed, a double-headed pawl reciprocated by said speed-changing mechanism and adapted to engage either face of said ratchet, a steam-cylinder, a pistonhead, a spring and a piston-rod adapted to control said double-headed pawl, substantially as described.

7. The combination in apparatus for the combustion of pulverized fuel, of a reservoir for said fuel, a blast apparatus for projecting the fuelinto the furnace, a feeding device for conveying the powdered fuel from the reservoir to said blast apparatus, and speed-changing mechanism for said feeder, comprisinga ratchet-wheel having teeth on both faces, the teeth of one face being right-handed and those of the other lefthanded, a double headed pawl reciprocated by said speed changing mechanism and adapted to engage either face of said ratchet, a steam-cylinder, a pistonhead, a spring, a piston-rod adapted to control said double-headed pawl and means such as the gland 45 and disk 46 for adjusting the compression of said spring, substantially as described.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

GEORGE S. EMERIOK.

Witnesses:

ARTHUR E. NITZSCHE, H. Bovnn SOHERMERHORN. 

